Running a small polyolefin pipe extruder with a high-speed "hyper drive" doubles output without any extra gear wear, says Cincinnati Extrusion, Erlanger, Ky. These claims are based on trials of prototype Rapidex single-screw extruders in Germany. An extra-long, 60-mm, 37:1 extruder is fitted with a 250-kw, water-cooled Siemens AC motor, which would normally power a 120-mm extruder. That allows screw speeds up to 450 rpm (vs. the usual 220-rpm limit) with the aid of a special fluted bushing to couple the gear shaft and screw. Output is 2200 lb/hr of PE pipe or 1760 lb/hr of PP pipe, more than double the usual rates for a 60-mm extruder. Downstream cooling and handling equipment is sized for a 120-mm extruder. The extruder is modified with a grooved feed section and new screw geometry to allow twice the normal feed rate. The Rapidex line was unveiled last August and is being tested in production at Rehau in Viechtach, Germany, and other locations, making 160-mm HDPE pipe with 5.8-mm wall thickness. Tel: (859) 746-1530 . www.cet-austria.com